The polar bear, Ursus maritimus, or the sea bear, evolved about 200,000 years ago from brown bear ancestors. They are superbly adapted for survival in the Far North.
Polar bears range throughout the Arctic in areas where they hunt seals at openings in sea ice called leads. Five nations have polar bear populations: the United States (Alaska), Canada, Russia, Denmark (Greenland), and Norway.
Polar bears are the world's largest land predators. They top the food chain in the Arctic, where they prey primarily on ringed seals.
Adult male polar bears weigh from 775 to more than 1,500 pounds. Females normally weigh 330 to 550 pounds.
Females usually bear two cubs. Single cubs and triplets also occur depending on the health and condition of the mother. Cubs stay with their moms for up to 2-1/2 years.
